Restoration of ecosystem services in tropical forests: A global meta-analysis

To reverse the effects of deforestation, tropical areas have expanded restoration efforts in recent years. As ecological restoration positively affects the structure and function of degraded ecosystems, understanding to what extent restoration recovers ecosystem services (ES) is an important step in directing large-scale restoration actions. We evaluated the effect of restoration in increasing the provision of ES in tropical forests. We performed a global meta-analysis of ecological indicators of the ES provided in restored areas, degraded areas and reference ecosystems. We tested for the effects of different restoration strategies, different types of degradation and for the effects of restoration over time. Overall, restoration actions contributed to a significant increase in levels of ecological indicators of ES (carbon pool, soil attributes and biodiversity protection) compared to disturbed areas. Among the restoration strategies, the natural regeneration was the most effective. Biodiversity protection and carbon recovered better than soil attributes. All other restoration strategies recovered ES to a substantially lesser degree, and reforestation with exotics decreased the ES of areas degraded by agriculture. In areas degraded by pasture, restoration was more effective in recovering the biodiversity protection, whereas in areas degraded by agriculture, the restoration recovered mainly the carbon pool. Our results show that by choosing the correct strategy, restoration can recover much of the ES lost by the degradation of tropical forests. These results should be considered for large-scale conservation and management efforts for this biome.

为逆转森林砍伐带来的负面影响，近年来热带地区逐步扩大了生态修复工作的实施规模。鉴于生态修复对受损生态系统的结构与功能具有积极改善作用，明确生态修复可在多大程度上恢复生态系统服务（ecosystem services, ES），是指导大规模修复行动的关键一环。本研究针对热带森林开展相关评估，以明确修复举措对提升生态系统服务供给水平的效果；我们通过对修复区、退化区及参照生态系统所提供的生态系统服务的生态指标开展全球荟萃分析，同时检验了不同修复策略、不同退化类型以及修复时长对生态系统服务恢复的影响。总体而言，相较于受干扰区域，生态修复行动可显著提升生态系统服务相关生态指标（碳库、土壤属性与生物多样性保护）的水平。在各类修复策略中，自然再生手段的修复效果最为显著；生物多样性保护与碳库恢复的成效优于土壤属性修复。其余修复策略的生态系统服务恢复效果均明显较弱，而采用外来树种的造林举措反而会降低农业退化区域的生态系统服务水平。在牧场退化区域中，修复举措对生物多样性保护的恢复效果更为显著；而在农业退化区域中，修复则主要助力碳库的恢复。本研究结果显示，通过选择恰当的修复策略，生态修复可大幅恢复热带森林退化所丧失的大部分生态系统服务。上述结论可为该生物群区的大规模保护与管理工作提供重要参考依据。